In many parts of the country, summer is often a synonym for "blast furnace" and can be downright hot and miserable. If you find yourself in such a climate, it's imperative that you drink plenty of water to beat both the heat and heat-related injuries. Your teeth and gums are another reason to keep hydrated during those hot summer months.

Your body needs water to produce all that saliva swishing around in your mouth. When you have less water available in your system, the production of this important bodily fluid can go down—and this can increase your risk of dental disease. That's because saliva performs a number of tasks that enhance dental health. It helps rinse the mouth of excess food particles after eating that could become a prime food source for disease-causing bacteria. It also contains antibodies that serve as the first line of defense against harmful microorganisms entering through the mouth.

Perhaps saliva's most important role, though, is protecting and strengthening enamel, the teeth's outer "armor" against disease. Although the strongest substance in the body, enamel has one principal foe: oral acid. If the mouth's normally neutral pH becomes too acidic, the minerals in enamel begin to soften and dissolve. In response, saliva neutralizes acid and re-mineralizes softened enamel.

Without a healthy salivary flow protecting the mouth in these different ways, the teeth and gums are vulnerable to assault from bacteria and acid. As they gain the upper hand, the risk for tooth decay or periodontal (gum) disease can skyrocket. Keeping yourself adequately hydrated ensures your body can produce an ample flow of saliva.

By the way, summer heat isn't the only cause for reduced saliva: Certain prescription medications may also interfere with its production. Chemotherapy and radiation, if targeting cancer near the head or neck, can damage salivary glands and impact flow as well.

If you have reduced saliva from medication you're taking, talk to your doctor about switching to an alternative prescription that doesn't affect saliva production. If you're undergoing cancer treatment, be extra vigilant about your oral hygiene practice and regular dental visits. And as with summer heat, be sure you're drinking plenty of water to help offset these other effects.

Even when it's hot, summertime should be a time for fun and relaxation. Don't let the heat ruin it—for your health or your smile.